The oxygen isotope composition of nitrogen oxides (NOx) in the atmosphere is a useful tool for understanding the oxidation of NOx into nitric acid / nitrate in the atmosphere. A set of experiments was conducted to examine change in isotopic composition of NOx due to NOx–O2– O3 photochemical cycling. At low NOx / O2 mixing ratios, NOx became progressively and nearly equally enriched in 17O and 1...

INTRODUCTION One of the main functions of cutaneous tissues is to protect our body from the outdoor insults. Ozone (O3) is among the most toxic stressors to which we are continuously exposed and because of its critical location, the skin is one of the most susceptible tissues to the oxidative damaging effect of O3. O3 is not able to penetrate the skin, and although it is not a radical per se, t...

Ozone (O3) exposure stimulates airway inflammation and epithelial sloughing in a number of species, including mice. Platelet-activating factor (PAF) is a lipid mediator released by activated mast cells, macrophages, and epithelial cells and causes pulmonary inflammation and hyperpermeability. We hypothesized that the activation of PAF receptors is central to the development of inflammation and ...

[1] The kinetics of ozone (O3) chemistry and its two main precursors, nitrogen oxides (NOx) and volatile organic compounds (VOC), represents an important field of uncertainty in atmospheric chemistry and photochemical modeling. This uncertainty affects the design of control strategies to reduce tropospheric O3 production. The effect of controlling ozone precursors on sensitivity regimes was eva...

The impact of ozone (O3) on the production and utilization of photoassimilates was examined in Plantago major population ‘Valsain’. Plants were exposed in controlled environment chambers to either charcoal/Purafil-filtered air (CFA) or CFA plus O3 (15 nmol mol −1 O3 overnight rising to a maximum of 75 nmol mol −1 between 12:00 and 16:00 h). Measurements of leaf gas exchange and non-structural c...

Risks associated with exposure of individual plant species to ozone (O3) are well documented, but implications for terrestrial biodiversity and ecosystem processes have received insufficient attention. This is an important gap because feedbacks to the atmosphere may change as future O3 levels increase or decrease, depending on air quality and climate policies. Global simulation of O3 using the ...

OBJECTIVES Ozonated autohemotherapy (O3-AHT) has been used to effectively treat gout, but the underlying therapeutic mechanisms remain unknown. In this study, as an initial effort to understand the therapeutic mechanisms of O3-AHT, we aim to examine the effect of O3-AHT on serum inflammatory cytokine levels in gouty patients. PATIENTS AND METHODS Three groups of patients and healthy subjects ...

A mixed-phase chemistry box model is applied to study heterogeneous chemistry and its effect on tropospheric gas-phase chemistry, particularly on photochemical production of O3 and photochemical indicators for O3-NOx-hydrocarbon sensitivity, under a variety of atmospheric conditions ranging from remote marine to heavily-polluted atmospheres. A subsequent sensitivity analysis of the mixed-phase ...

Western U.S. near-surface ozone (O3) concentrations are sensitive to transported background O3 from the eastern Pacific free troposphere, as well as U.S. anthropogenic and natural emissions. The current 75 ppbv U.S. O3 primary standardmay be lowered soon, hence accurately estimating O3 source contributions, especially background O3 in this region has growing policy-relevant significance. In thi...

BACKGROUND Toll-like receptor 4 (TLR4) is involved in ozone (O3)-induced pulmonary hyperpermeability and inflammation, although the downstream signaling events are unknown. OBJECTIVES The aims of our study were to determine the mechanism through which TLR4 modulates O3-induced pulmonary responses and to use transcriptomics to determine potential TLR4 effector molecules. METHODS C3H/HeJ (HeJ...